1. Field of the Invention
The invention relates to a biopsy needle. More particularly, the invention relates to a biopsy needle having a sample recess shaped and dimensioned to optimize operation of the biopsy needle. The invention also relates to a method for forming the recess.
2. Description of the Prior Art
Biopsy needles are currently available in gauges ranging from 14 to 20. The biopsy samples are obtained using various methods. One of the commercially available designs employs a solid, pointed cannula inside of a slip-fitted outer cannula with a beveled leading end. The solid inner cannula contains a rectangular cavity, which collects the biopsy sample. The biopsy sample is removed from the tissue by inserting the biopsy needle into the tissue, uncovering the collection portion, that is, the rectangular cavity, and firing the outer cannula forward quickly using a spring. The portion of the tissue in the region of the sample collection rectangular cavity is torn from the surrounding tissue and collected in the rectangular cavity. Biopsy sample collection using this “brute force” approach results in trauma to the patient. A need exists, therefore, for a biopsy needle that obtains the desired sample by cutting rather than tearing the sample from the surrounding tissue.